The proposed research is designed: (1) to determine the amounts and kinds of genetic variability that can be detected in higher organisms using restriction enzymes and molecularly cloned DNA probes; and (2) to utilize the information gained to study the evolutionary genetics of a species complex at the population, interspecific, and intergeneric levels. The basic materials will include two experimental plant populations which are particularly useful for this study because many aspects of their population genetics and evolution have already been characterized in terms of allozymes, morphological polymorphisms, measurement characters and disease reaction. Thus, the proposed molecular genetic research will be integrated with a detailed long-term study of fundamental genetic mechanisms and evolutionary processes. This integration of molecular genetics with population and evolutionary genetics is expected to contribute significantly to basic biological research and so to health-related research.